Virus-Induced Gene Silencing in Chrysanthemum seticuspe Using the Tomato Aspermy Virus Vector

Chrysanthemum is one of the most economically important flowers globally due to its high ornamental value. In recent years, a large percentage of the Chrysanthemum seticuspe genome has been determined, making this species useful as a model chrysanthemum plant. To fully utilize the genome's information, efficient and rapid gene functional analysis methods are needed. In this study, we optimized the tomato aspermy virus (TAV) vector for virus-induced gene silencing (VIGS) in C. seticuspe. Conventional plant virus inoculation methods, such as the mechanical inoculation of viral RNA transcripts and agroinoculation into leaves, did not achieve successful TAV infections in C. seticuspe, but vacuum infiltration into sprouts was successful without symptoms. The TAV vector harboring 100 nucleotides of the phytoene desaturase (PDS) gene caused photobleaching phenotypes and a reduction in CsPDS expression in C. seticuspe. To our knowledge, this is the first report of VIGS in chrysanthemums.